he laugh? However, if there is no auxiliary or copula present, inversion requires the introduction of an auxiliary in the form of do-support: I know. → Do I know? (Compare: *Know I?) He laughs. → Does he laugh? (Compare: *Laughs he?) She came home. → Did she come home? (Compare: *Came she home?) The finite (inflected) verb is now the auxiliary do; the following verb is a bare infinitive which does not inflect: does he laugh? (not laughs); did she come? (not came). In negated questions, the negating word not may appear either following the subject, or attached to the auxiliary in the contracted form n't. That applies both to do-support and to other auxiliaries: Why are you not playing? / Why aren't you playing? Do you not want to try? / Don't you want to try? The above principles do not apply to wh-questions if the interrogative word is the subject or part of the subject. Then, there is no inversion and so there is no need for do-support: Who lives here?, Whose dog bit you? The verb have, in the sense of possession, is sometimes used without do-support as if it were an auxiliary, but this is considered dated. The version with do-support is also correct: Have you any idea what is going on here? Do you have any idea what is going on here? (Have you got any idea what is going on here? – the order is similar to the first example, but have is an auxiliary verb here) For elliptical questions and tag questions, see the elliptical sentences section below. With not In the same way that the presence of an auxiliary allows question formation, the appearance of the negating word not is allowed as well. Then too, if no other auxiliary or copular verb is present, do-support is required. He will laugh. → He will not laugh. (not attaches to the auxiliary will) She laughs. → She does not laugh. (not attaches to the added auxiliary does) In the second sentence, do-support is required because idiomatic Modern English does not allow forms like *She laughs not. The verb have, in the sense of possession, is sometimes negated thus: I haven't the foggiest idea. Most combinations of auxiliary/copula plus not have a contracted form ending in suffix -n't, such as isn't, won't, etc. The relevant contractions for negations formed using do-support are don't, doesn't and